Replaceable body saver

ABSTRACT

A high pressure valve includes a valve body having a surface defining a corresponding portion of a conduit and a pocket. A removable insert is removably inserted into the pocket of the valve body and has surface defining a corresponding portion of the conduit. A seal insert is spaced from the valve body by the removable insert and has an interface with the removable insert. A moving member interfaces with the seal insert for selectively closing the conduit, the interface between the seal insert and the removable insert allows play between the seal insert and the removable insert in response to movement of the moving member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/008,970, filed Jun. 14, 2018, entitled REPLACEABLE BODY SAVER andpublished as US 2019-0346048 A1. U.S. patent application Ser. No.16/008,970 claims benefit of U.S. Provisional No. 62/670,537 filed onMay 11, 2018. The Publication US 2019-0346048 A1 and the patentapplication Ser. No. 16/008,970 and No. 62/670,537 are each incorporatedby reference herein in their entirety.

TECHNICAL FIELD

This invention relates in general to fluid drilling equipment and inparticular to high pressure valves subjected to severe operatingconditions, such as the high pressures, high flow rates, and abrasivefluids commonly found in hydraulic fracturing operations and other oiland gas drilling applications.

BACKGROUND

Gate and plug valves have a service life that is limited by thecondition of the main body. Internal parts can be replaced buteventually the deterioration of the sealing insert to main bodyinterface, due to corrosion, wear, erosion and eventual washout, whichleads to an unusable main body. The damaged main body typically needs tobe repaired in an intrusive manner such as welding. The root cause ofthis deterioration is the inherent design of these types of valves,which including small gaps between the internal sealing parts that allowmovement of the main sealing interface (e.g., the displacement of thegate between the seats of a gate valve and the rotation of a plugbetween the inserts in a plug valve). Without these gaps, the gate orplug will lock-up due to friction. The tolerances of these gaps are alsoaffected by the temperature and/or pressure inside the valve.

In one of the most severe service applications known today, hydraulicfracturing (“fracing”), very high pressure slurry is pumped throughthese valves at very high rates. In fracing, fracing slurry is forceddown a wellbore with enough pressure to fracture the hydrocarbon bearingrock formations and force particulates into the resulting cracks. Whenthe pressure is released, the particles (“proppant”), which may be sandor other high compressive strength additives such as ceramic particlesand bauxite, remain in the factures (cracks) and keep the fracturesopen. This “mechanism” then allows pathways for hydrocarbon to flow fromthe rock that was previously solid. The particle size distribution inthese facing fluids is distributed so that the larger particles can propopen larger cracks and finer particles can prop open the very tips ofthe cracks, which are microscopic in nature. The particle sizes can varyfrom 0.004 inches to 0.01 inches (No 140 Mesh to No 8 Mesh). The pumpingpressure at the valve can be up to 15,000 psi and the slurry velocitythrough a valve bore of 5.125 inches, as is typical of a 5⅛ inch, 15000psi valve, is well above erosional velocity of about 50 to 70 feet persecond. Moreover, the fracing is typically preceded and followed by anacid wash of 15% hydrochloric acid, which accelerates corrosion.

As one skilled in the art of mechanical engineering can ascertain, thefracing “mechanism” will inject proppant particles into any crack,orifice or possible leak path in the valve assembly. The injectedparticles remain in the valve assembly when the pressure is released.Small particles as large as 0.004 inches are within machining tolerancesof steel parts and therefore will find their way into metal sealingsurfaces. With the high velocity of abrasive fracing fluid, any weaknessor point of turbulence can very quickly lead to a washout of a seal areaor any interface. If an area or interface adjoins the valve main body,then the life of the main valve body is severely limited.

To preserve the main moving sealing parts and to allow them to sealeffectively, very high viscosity sealing greases are injected and thevalves (both gate and plug valves) are greased as many times aspracticable on a job. Greasing forces the proppant out of the interfacesto allow effective sealing and prevent scouring of the seal surfaceswith trapped particles. Even with this procedure, the moving sealingfaces have a very limited service life and are replaced frequently.

For the critical main valve body to seat interfaces, many solutions havebeen presented for this problem. For gate valves, U.S. Pat. No.9,261,196, assigned to GE, discloses a seal to exclude sand and U.S.Pat. No. 8,689,886, assigned to Vetco, discloses hardened seat and bodyfaces with metal sand excluders. For plug valves, applications US2016/0201811, assigned to GE, and U.S. Pat. No. 9,987,223, assigned toTechlock, show attempts at minimizing these gaps with complex seals andin some cases multiple interfaces. The shortcoming of these recentexamples, as well as numerous previous attempts, is their failure toaddress the fundamental root cause of body failure, namely, for the veryexistence of an interface between the main valve body and a sealinginsert.

Another method that has been used to extend the life of the valve islining the inner bore of the valve with tougher metal than that of thevalve body itself. Such solutions for gate valves are presented in U.S.Pat. No. 7,481,239, assigned to Stinger, and more recently in USapplication 2017/0191570, assigned to Valveworks. With the increasingfrac flow rate velocities the typical low alloy valve steel, such as4130, required tougher steel liners, such as 4340 alloy steel, andprecipitation hardening martensitic steels, such as steels in the 17-4PH range. These solutions have many additional parts and nonethelessstill have gaps in their assemblies, which leads not to direct failureof the valve body, but instead of the liners. Plug valves have beenlined similarly as disclosed in U.S. Pat. No. 7,204,474, assigned toStinger, with the linings attempting to prevent the whole bore of thevalve from eroding.

Today, with the higher pressures and higher frac flowrates, largervalves are being constructed directly from the higher strength steelslike 4340 and 17-4 PH steel. These hold up well, although lining thebore does not provide any additional benefit. These steels are difficultand time intensive to weld repair, and therefore a cost effective andsimple method is required to preserve the main deterioration point ofthese valves, namely, the seal insert to body area. Preserving the sealinsert to body area will thereby extend the service life of the highercost high strength and low corrosion steel bodies.

SUMMARY

One representative embodiment of the present inventive principles is ahigh pressure valve, which includes a valve body having a surfacedefining a corresponding portion of a conduit and a pocket. A removableinsert is removably inserted into the pocket of the valve body and hassurface defining a corresponding portion of the conduit. A seal insertis spaced from the valve body by the removable insert and has aninterface with the removable insert. A moving member interfaces with theseal insert for selectively closing the conduit, the interface betweenthe seal insert and the removable insert allows play between the sealinsert and the removable insert in response to movement of the movingmember.

Advantageously, erosion, corrosion or other damage is isolated to theremovable annular insert, rather than the valve body. When the removableinsert has sustained an unacceptable degree of damage, it can be removedand replaced or re-machined. In addition, the principles of the presentinvention also allow for removal and replacement of removable insertwithout resort to intrusive techniques, such as welding.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference is now made to thefollowing description taken in conjunction with the accompanyingDrawings in which:

FIG. 1a is a schematic side cross-sectional view of a prior art gatevalve;

FIG. 1b is schematic side cross-sectional view showing in further detailof gate valve seat to body sealing of the gate valve shown in FIG. 1 a;

FIG. 2 is a schematic side view of another prior art gate valve with adouble seat gate to body sealing;

FIG. 3 is a schematic cross-sectional side view of a prior art plugvalve;

FIG. 4a is a schematic cross-sectional side view of a prior art plugvalve with a double seat design;

FIG. 4b is a schematic cross-sectional side view showing in furtherdetail the double insert seat art of the plug valve of FIG. 4 a;

FIG. 5a is a schematic block cross-sectional side view of an exemplarygate valve to explain the problem being addressed by the embodiments ofthe present invention;

FIG. 5b shows further details of the valve body to seal interface of thevalve of FIG. 5 a;

FIG. 5c shows further details of the valve body to seal interface of thevalve of FIG. 5a with erosion;

FIG. 6 is a schematic block cross-section side view of a representativegate valve according to one embodiment of the present invention;

FIG. 7 is a schematic block cross-sectional side view of a plug valveillustrating the problem being addressed by the principles of thepresent invention;

FIG. 8 is a schematic block cross-sectional view of a plug valveillustrating the solution given by the principles of the presentinvention;

FIG. 9 is a schematic cross-sectional side of plug valve with taperedinsert according to a representative embodiment of present invention;

FIGS. 10a and 10b show further details of portions of the plug valve ofFIG. 9;

FIG. 11a is a schematic cross-sectional side view of a gate valveaccording to an embodiment of present invention;

FIGS. 11b and 11c show further details of portions of the gate valve ofFIG. 11a in further detail.

DETAILED DESCRIPTION

The problems being solved and the solutions provided by the embodimentsof the principles of the present invention are best understood byreferring to FIGS. 1 to 11 of the drawings, in which like numbersdesignate like parts.

FIG. 1a shows a prior art gate valve 10 of a design used for severeservice high pressure fracing applications. Gate valve 10 has a gate 11that can move in a sliding movement against a seal insert 12 andperpendicularly to the bore of a valve body 13.

FIG. 1b is a schematic side view drawing showing in detail the sealinsert 12 to valve body 13 bore sealing interface. Note that thisinterface has a gap, as all gate valves do, to allow tolerance formoving the gate. This gap is the root cause of the failure of gatevalves as will be explained in detail below. In fracing applications,frac sand will penetrate this gap, even with the sand excluder 14 inthis design, and eventually the seal areas in the gap corrode, erode andultimately wash out.

FIG. 2 is a schematic block cross-sectional side view of a prior artgate valve with a double seat solution. This gate valve has a gate 15and an inner seat 16 engaged with an outer seat 17. This outer seat 17is inserted with a seal into the body 18. The example of FIG. 2illustrates that some gate valve designs have two parts making up thestationary seal assembly, with both pieces gapped and seals covering thegaps. This type of design also fails rapidly in fracing applications dueto the penetrative properties of the fracing slurry.

FIG. 3 is a schematic cross-sectional side view of a prior art plugvalve having plug 19 sealing in a rotating fashion against stationaryinserts 20. These inserts 20 are sealed against the body 21 and have atolerance gap at 22 to allow the plug 19 to move. Typical failure of thebody is in the region of the seal 23 with frac sand penetrating the gap22, opening it to corrosion and erosion and eventual failure, which is avery rapid process under fracing conditions with acid washes.

FIGS. 4a and 4b are respectively schematic cross-sectional and detailedviews of a double insert seat of a prior art plug valve. FIG. 4a showsvalve body 24 having a plug 25 that can seal in a rotating fashionagainst an insert assembly consisting of two pieces 26 and 27. In FIG.4b , the detail of the seal assembly is shown to illustrate that someplug valve designs have two parts making up the stationary insertassembly. In these designs, both pieces are gapped with seals coveringthe gaps. This type of design also fails rapidly in fracingapplications, with the typical failures being in the area of the seal 28of FIG. 4b due to the gap at interface 29.

FIG. 5a illustrates the root cause of washout in valves used in severeenvironments, such as those found during fracing operations. Inparticular, FIG. 5a is a schematic block diagram of a cross-section of aportion of a typical gate valve configuration with a body 30, sealinsert 31 and gate 32, which moves in a perpendicularly back and forthin the direction indicted by arrow 33. The valve bore 20 is associatedwith an arrow 34 showing the direction of pressure force, assuming thevalve is closed. A center line 35 of the valve bore is shown forreference.

One of the main moving seal interfaces is shown at 36 between thestationary seal insert 31 and the gate 32. When the valve is closed, thegate 32 is pushed to the right to seal on a seal similar to seal insert31, but on the opposing side of gate 32 (not shown). Due to thenecessary tolerance gaps to allow movement of the gate 32, when thewhole assembly is forced to the right under high pressure, the sum ofall these tolerances opens a small gap at interface 37, resulting in agap 37, as shown in FIG. 5b . Typically, some sort of seal is in the gap37, which is exemplified by an O-ring 38, though the actual seals maydiffer from design to design as illustrated by the prior art.

When pressure is applied in the opposite direction of arrow 34, then gap37 closes and a corresponding gap opens on the opposite side of the gateand seat assembly (not shown). The back and forth movement 39 wears outthe metal in the gap 37, as shown in FIG. 5b in the form of a cavity 40.Once this mechanism, which is aided by erosion and corrosion, creates alarge enough cavity 40, the seal area fails and rapid washout of thebody part as well as insert occurs. The presence of frac sand, which isdesigned to penetrate into the smallest cracks, aids this processsignificantly, given that frac sand is a hard material.

This mechanism is repeated in a mirror fashion on the other side of thegate on the other seat and seat pocket. As one skilled in the art canappreciate, a valve operating under fracing conditions must sealbi-directionally while being actuated multiple times during a fracingoperation, which results in very rapid failure at the seal-bodyinterface and damage to main body. The insert 31 can of course bereplaced, but the rapid deterioration of the body 30 at the interface 37leads to severely shortened service life of the main body of the valve,requiring replacement or intrusive repair like welding and machining.

Referring back to FIGS. 1a, 1b and 2, all gate valve designs require agap similar to gap 37 of FIGS. 5a-5b for providing sufficient toleranceto allow the gate to move. Hence, all current gate valve designs aresubject to the same failures described immediately above. Furthermore,an ionic fluid, such as hydrochloric acid, is commonly used before orafter fracing operations, in addition to other additives in thefracturing fluid. The ionic fluid and fracturing fluid additives canaccelerate galvanic corrosion in the gap, given that stationary sealinginserts are often made of different steel grades or other materialcombinations having different positions on the galvanic table. Thesedifferences in steel grade, while small, are significant in the presenceof the 15% hydrochloric acid concentrations often used in fracingoperations.

FIG. 6 is a schematic block cross-sectional view of a portion of anexemplary gate valve embodiment according to the principles of thepresent invention. According to the principles of the present invention,an annular body saver 115 is disposed between the annular portion ofvalve body 110 and the stationary sealing insert 112. In order for thegate valve to work as designed, a gap 116 must still exist between thebody saver 115 and the stationary seal insert 112. The exemplary valvealso includes gate 114, which moves in accordance with arrow 113, sealinsert to gate interface 118, and cylindrical bore 120 having a borecenterline 122.

The body saver 115 according to the present principles advantageouslyfunctions as a replaceable part that preferentially sees wear so thatthe integrity, and therefore the service life, of the valve body 110 isnot affected. In particular, the annular body saver 115 is rigidly fixedto within an annular pocket within the annular portion of valve body 110so that there is substantially no gap at interface 117 nor any movementtolerance that would open a gap at interface 117. This configurationensures that the body saver 115 to body 110 interface 117 does notdeteriorate by the mechanisms described earlier as the root cause, theexistence of a gap is removed by this design.

When the expected interface wear at gap 116 is a sufficient to riskfailure, the body saver 115 is removed and replaced together with a newseal insert 112. Preferably, the body saver 115 is not a bore saver, butinstead saves the highest wearing location in a gate valve, namely, theseat pocket. According to the present principles, the body saver 115 hasone or more of the following features: a) be made from the same materialas the body 110 to avoid any galvanic corrosion issues; b) have asealing system, which can consist of seals in the body saver 115 and/orthe body 110; c) be rigidly affixed to the body so that there is nomechanical gap at interface 117—for example, this fixation can bescrewed, threaded, interference fit or based on another type ofretaining mechanism such as a retaining or snap ring; d) have a positivesand exclusion seal preferentially placed as close to the body 110 boreside of interface 117; e) be removable and replaceable withoutmachining, cutting, welding or other method interfering directly withthe integrity of the main body 110; and f) have no protrusions into themain bore or tapers or other features that could cause turbulence andrapid erosion under fracing conditions.

Eventually, under the harsh conditions of fracing, even the interface117 could deteriorate. In this case, the body saver 115 is removed, theannular pocket within the valve body 110 around interface 117 ismachined further axially into the bore. Then a new slightly longer bodysaver is installed and the valve can continue service with the same sealinsert 112 type. All this is advantageously achieved without a costlyweld repair.

The principles of the present invention also advantageously apply toplug valves. FIG. 7 is a schematic block cross-sectional view of arepresentative plug valve. Common parts like body 110, bore 120, centerline 122, and pressure direction 111 are the same as the exemplary gatevalve embodiment of FIG. 6.

A cylindrical plug 119 rotates clockwise and anticlockwise by ninetydegrees, as shown by arrow 121. A stationary insert 124 is installedbetween the plug 119 and the body 110 and is typically tapered (notshown) and forced into the bore 120 to minimize the gaps at interface123 between the plug 119 and the stationary insert 124. At the extremepressures needed for fracing, plug valves have a metal to metal seal atinterface 123, typically aided by very high viscosity greasing sealant.The interface between the stationary insert 126 and the body 110 usuallyhas some sort of soft seal and a gap to give the necessary tolerancerequired to allow rotational movement of the plug 119 with respect tothe insert, without locking up due to excessive friction.

For a plug valve, the deterioration of the body 110 occurs at interface126. Generally, the deterioration mechanism is similar to that of a gatevalve, since the required tolerances for rotation require some lateralmovement at interface 126 as the pressure of arrow 111 is reversed. Thisback and forth motion allows the very small frac sand particles to enterthe interface area 126 leading to erosion, corrosion and eventualfailure of the seal at that interface.

FIG. 8 is a schematic block cross section view of a portion of arepresentative plug valve embodying the principles of the presentinvention. An annular body saver 125 is installed in an annular pocketwith a new interface 127 with the annular portion of valve body 110. Agap is formed at an interface 126 of the seal insert 124 with the bodysaver 125 to allow plug 119 to move. The body saver 125 is rigidly fixedto the body 110 with no gap at interface 117. In this embodiment, wearwill occur on the body saver 125, at interface 126 thus preserving thevalve body 110 at interface 127.

Preferably, the body saver 125 will have features similar to features a)to f) discussed earlier with regards to the gate valve embodiment. It isalso possible here, if there is a long-term deterioration of interface127, to machine deeper axially into the end wall of the pocket withinvalve body 110 and installing a correspondingly longer body saver 125.

FIG. 9 depicts a cross section of plug valve with tapered insertsaccording to the principles of the present invention. For discussionpurposes, this plug valve design is a 5⅛ inch bore, 15,000 psi workingpressure valve. Some common structures from FIG. 8, including valve body110, cylindrical bore 120, centerline 122, plug 119, interface 123between plug and tapered seal insert 124, and interface 126 between sealinsert 124 and body saver 125 have also been assumed for discussionpurposes. The interface 127 between the body saver 125 and the valvebody 110 is indicated.

In FIG. 10a , cylindrical plug 119 rotates with respect to stationarytapered annular seal insert 124 at interface 123, 129 is an empty gap,128 is the main seal between the annular tapered seal insert 124 and thebody saver insert 125. An annular space 141 is disposed within thestationary insert 124 between plug 119 and stationary insert 124, thisis a sealant grease groove that acts as an assistance seal to the metalsealing interface 123. The annular body saver 125 is sealed to the mainbody 110 at distinct sealing points: seal 130, which could be anelastomeric seal that is situated in the body saver 125; seal 131, whichcould be an elastomeric seal that is situated in the body 110; and seal135, which is a metal to metal interference seal, shown in detail inFIG. 10b . The seal 128 in the body saver 125 is in the exact sameposition and spatial orientation as it would be present in the valvebody 110, were there no body saver installed, the space being solidmetal that is an integral part of the valve body. Guide pin 142 servesto correctly orientate the body saver insert 125, which has a taperedcylindrical profile at interface 126 concurrent with the tapered sealinsert 124. The other items making up the assembly are a round snap ring132 and a retainer 133. The body saver 125 is installed in the bodywithout the plug 119 and tapered insert 124 being present. The bodysaver insert 125 is inserted with the guide pin orienting it into thebody 110.

Referring to FIG. 10b , the integral metal lip 136 of the body saver 125has an interference fit with the valve body 110 at interface 135. Thebody saver 125 is installed with a compression tool so that the seals130 and 131 completely fill their grooves and there is no gap atinterface 127. The metal lip 136 engages slightly before full closure ofthe gap at interface 127, and when gap is closed, it has a preloadedmetal to metal contact with the valve body 110 along the circumferenceof the cylindrical bore 120 along interface 135, thus excluding any sandpenetration. With the body saver 125 held in place, a circular crosssection retaining ring 132 is installed the location shown. Then theretainer 133 is inserted with an interference fit to keep the retainingring 132 in place. The retainer 133 has a gap feature 134 that ensures afurther metal to metal seal this point (not shown). Then theinstallation compression tool can be removed and a seal 128 installed.The body saver 125 is now a rigid part of the body 110, with no gap at127. All the wear will take place at interface 126 between the insert124 and the body saver 125 in the vicinity of the seal 128 which is themain corrosion and erosion point of this design. Once the erosion invicinity of seal 128 becomes significant enough to affect the sealingperformance or risk a washout, this being determined by visualinspection during maintenance, the body saver 125 can be un-installedand a new one installed. This allows significant extension of the mainbody 110 life.

This design has all the features listed earlier: a) the body saver 125is of the same steel as the valve body 110; b) there two elastomericseals, seal 130 in the body saver 125 and seal 131 in the body 110; c)the body saver 125 is rigidly affixed to the body 110 by a retainer ring132 secured with a retainer 133 so that there is no mechanical gap atinterface 127; d) a positive metal sand exclusion seal 136 is disposedclose to the body bore 120 side of interface 137; e) the body saver 125can be simply removed by reversing the installation procedure; and f)there are no protrusions into the main bore 120 or tapers or otherfeatures that could cause turbulence and rapid erosion under fracingconditions, as shown in FIG. 10b . The small depression at interface137, at the point of intersection between body saver 125 and body 110,is engineered to be the same as the meeting of two 5⅛″ 15,000 psi APIflange faces with a BX seal ring installed, which has been found not tocause sufficient turbulence for erosion.

FIG. 11a is a cross section of gate valve showing an embodiment ofpresent invention, with further details provided in FIGS. 11b and 11c .Some common structures of FIG. 6 have been assumed for discussionpurposes, including body 110, cylindrical bore 120, centerline 122, gate114, interface 118 between moving gate 114 and stationary gate sealinginsert 112. The body saver 115 has a different sealing profile atinterface 116 compared to that of body saver 125 of FIGS. 9 and 10.However the parts inserted into the body 110 are substantially the same.The body saver 115 seals to the main body 110 at interface 117.

The body saver 115 is sealed to the main body 110 at interface 117 withdistinct sealing points: seal 130, which could be an elastomeric sealthat is situated in the body saver 114; seal 131, which could be anelastomeric seal which is situated in the body 110; and seal 136 whichis a metal to metal interference seal shown in further detail in FIG.11c . (A guide pin would typically be at the upper part of the bore 120and FIG. 11b only shows the lower part of the bore 120). The functionand installation of the body saver insert 115 is the same as discussedfor body saver 125 of FIG. 10 and the interface 127 on a plug valve isequivalent to the interface 117 on a gate valve.

As can be seen from the description given and the detail in FIG. 11b ,it is possible to design the main failure point of the gate valve body110 at interface 116 away from the body 110 by the installation of thebody saver 115 which then contains the deteriorating interface 116. Inthe design shown in FIG. 11b , the sealing insert 112 has a greasegroove 141 and a main seal 128, but this could be any particular gatevalve seat design which may differ in detail.

Similar solutions as described in FIGS. 10 and 11 can be applied todiffering gate and plug valve designs, as well as for fluid conduitsthat experience body failure due to the mechanism described above inconjunction with FIG. 5. Thus one skilled in the art could design bodysavers with differences in retaining and/or sealing solutions thatretain the key common features of this invention which are: 1) rigidfixation of the body saver to the fluid conduit body; 2) no gap betweenthe body saver and valve body at the axial interface within the bore; 3)no protrusions into the fluid conduit bore or tapers or other disturbingfeatures; and 4) be removable and replaceable without machining,cutting, welding or other method interfering directly with the integrityof the fluid conduit body. In addition, the principles of the presentinvention may also be applied to such applications as production treevalves and flow-back operations.

Although the invention has been described with reference to specificembodiments, these descriptions are not meant to be construed in alimiting sense. Various modifications of the disclosed embodiments, aswell as alternative embodiments of the invention, will become apparentto persons skilled in the art upon reference to the description of theinvention. It should be appreciated by those skilled in the art that theconception and the specific embodiment disclosed might be readilyutilized as a basis for modifying or designing other structures forcarrying out the same purposes of the present invention. It should alsobe realized by those skilled in the art that such equivalentconstructions do not depart from the spirit and scope of the inventionas set forth in the appended claims.

It is therefore contemplated that the claims will cover any suchmodifications or embodiments that fall within the true scope of theinvention.

What is claimed is:
 1. A high pressure valve comprising: a valve bodyhaving a cylindrical sidewall defining a first portion of a cylindricalbore and an annular pocket having an end wall and a sidewall; the valvebody further defining an annular interface surface extending between theend wall of the annular pocket and the cylindrical bore; wherein theannular interface surface forms a first angle with the end wall of theannular pocket and a second angle with the cylindrical bore; an annularbody saver removably inserted into the annular pocket of the valve body,the annular body saver having an outer sidewall, a first end wall, aninner sidewall and an integral annular lip extending from the first endwall and having an inner surface and an outer surface; the annular bodysaver being configured such that the inner surface of the integralannular lip forms an angle with the first end wall such that duringinsertion of the annular body saver into the annular pocket of the valvebody, the integral annular lip will slightly engage the interfacesurface of the valve body when there is a gap between the first end wallof the annular body saver and the end wall of the annular pocket; theannular body saver being further configured such that upon completeinsertion of the annular body saver into the annular pocket of the valvebody there is no gap between the first end wall and the end wall of theannular pocket, the inner sidewall is in contact with the sidewall ofthe annular pocket, the outer sidewall defines a second portion of thecylindrical bore, and the integral lip has a preloaded metal to metalcontact with the valve body along the circumference of the cylindricalbore along the interface surface; a retaining ring removably inserted inan annular groove formed in the sidewall of the annular pocket, theannular groove disposed such that a shoulder formed on the innersidewall of the annular body saver blocks insertion of the retainingring into the annular groove until the annular body saver is completelyinserted into the annular pocket of the valve body and the integral liphas a preloaded metal to metal contact with the valve body, and theretaining ring is configured such that, once inserted into the annulargroove, a portion protrudes from the groove and bears against theshoulder to maintain the preloaded metal to metal contact between theintegral lip and the valve body; a seal insert disposed within a secondpocket of the valve body and having a first end wall disposed adjacentto a second end wall of the annular body saver to define an interfacetherebetween, and a second end wall; and a moving member for selectivelyclosing the cylindrical bore, the moving member having a sidewallinterfacing with the second end wall of the seal insert.
 2. The highpressure valve of claim 1, further comprising a retainer removablyinserted into an annular recess formed on the inner sidewall of theannular body saver adjacent to the shoulder, the retainer configured tohold the retaining ring in the annular groove of the valve body tomaintain the preloaded metal to metal contact between the annular bodysaver and the valve body.
 3. The high pressure valve of claim 2, whereinthe retainer is removably held in place between the annular body saverand the inner sidewall of the annular pocket with an interference fit.4. The high pressure valve of claim 2, wherein the retainer is removablyheld in place between the annular body saver and the inner sidewall ofthe valve body with a threaded connection.
 5. The high pressure valve ofclaim 1, wherein the annular groove formed in the sidewall of theannular pocket has a semicircular cross section and the retaining ringhas a circular cross section configured to seat in the semicircularannular groove.
 6. The high pressure valve of claim 5, wherein theretaining ring is a snap ring configured to seat in the semicircularannular groove.
 7. The high pressure valve of claim 1, furthercomprising a first elastomeric seal disposed in a first annular grooveformed in the first end wall of the annular body saver, the firstelastomeric seal filling the first annular groove when the annular bodysaver is completely inserted into the annular pocket of the valve bodyand the annular body saver has preloaded metal to metal contact with thevalve body, whereby there is no gap between the first end wall of theannular body saver and the end wall of the annular pocket.
 8. The highpressure valve of claim 7, further comprising a second elastomeric sealdisposed in a second annular groove formed in the end wall of theannular pocket, the second elastomeric seal filling the second annulargroove when the annular body saver is completely inserted into theannular pocket of the valve body and the annular body saver haspreloaded metal to metal contact with the valve body, whereby there isno gap between the end wall of the annular pocket and the first end wallof the annular body saver.
 9. The high pressure valve of claim 1,further comprising a third elastomeric seal disposed in a third annulargroove formed in the second end wall of the annular body saver, thethird elastomeric seal filling the third annular groove when the sealinsert is inserted into the second pocket of the valve body, wherebythere is no gap between the third elastomeric seal and the first endwall of the seal insert.
 10. The high pressure valve of claim 1, whereinthe movable member comprises a gate.
 11. The high pressure valve ofclaim 1, wherein the movable member comprises a plug.
 12. A highpressure valve comprising: a valve body having a cylindrical sidewalldefining a first portion of a cylindrical bore and an annular pockethaving an end wall and a sidewall; the valve body further defining anannular interface surface extending between the end wall of the annularpocket and the cylindrical bore; wherein the annular interface surfaceforms a first angle with the end wall of the annular pocket and a secondangle with the cylindrical bore; a tapered seal insert disposed within asecond pocket of the valve body and having a tapered outer wall and aninner wall; a moving member for selectively closing the cylindricalbore, the moving member having a sidewall interfacing with the innerwall of the tapered seal insert; an annular body saver removablyinserted into the annular pocket of the valve body, the annular bodysaver having an outer sidewall, a first end wall, an inner sidewall andan integral annular lip extending from the first end wall and having aninner surface and an outer surface; the annular body saver having anasymmetrical configuration from an uppermost portion to a lowermostportion to conform to the tapered outer wall of the tapered seal insert;the annular body saver being configured such that the inner surface ofthe integral annular lip forms an angle with the first end wall suchthat during insertion of the annular body saver into the annular pocketof the valve body, the integral annular lip will slightly engage theinterface surface of the valve body when there is a gap between thefirst end wall of the annular body saver and the end wall of the annularpocket; the annular body saver being further configured such that uponcomplete insertion of the annular body saver into the annular pocket ofthe valve body there is no gap between the first end wall and the endwall of the annular pocket, the inner sidewall is in contact with thesidewall of the annular pocket, the outer sidewall defines a secondportion of the cylindrical bore, and the integral lip has a preloadedmetal to metal contact with the valve body along the circumference ofthe cylindrical bore along the interface surface; and a retaining ringremovably inserted in an annular groove formed in the sidewall of theannular pocket, the annular groove disposed such that a shoulder formedon the inner sidewall of the annular body saver blocks insertion of theretaining ring into the annular groove until the annular body saver iscompletely inserted into the annular pocket of the valve body and theintegral lip has a preloaded metal to metal contact with the valve body,and the retaining ring is configured such that, once inserted into theannular groove, a portion protrudes from the groove and bears againstthe shoulder to maintain the preloaded metal to metal contact betweenthe integral lip and the valve body.
 13. The high pressure valve ofclaim 12, further comprising a retainer removably inserted into anannular recess formed on the inner sidewall of the annular body saveradjacent to the shoulder, the retainer configured to hold the retainingring in the annular groove of the valve body.
 14. The high pressurevalve of claim 13, wherein the retainer is inserted between the annularbody saver and the inner sidewall of the annular pocket with aninterference fit.
 15. The high pressure valve of claim 12, wherein anupper portion of the annular body saver is longer, measured parallel tothe bore from the first side wall to the second side wall, than a lowerportion of the annular body saver.
 16. The high pressure valve of claim12, wherein a gap is formed between the retainer and the tapered outerwall of the tapered seal insert, and the length of the gap, measuredparallel to the bore, is greater on an upper portion of the annular bodysaver than on a lower portion of the annular body saver.
 17. The highpressure valve of claim 12, further comprising a first elastomeric sealdisposed in a first annular groove formed in the first end wall of theannular body saver, the first elastomeric seal filling the first annulargroove when the annular body saver is completely inserted into theannular pocket of the valve body and the annular body saver has apreloaded metal to metal contact with the valve body, whereby there isno gap between the first end wall of the annular body saver and the endwall of the annular pocket.
 18. The high pressure valve of claim 17,further comprising a second elastomeric seal disposed in a secondannular groove formed in the end wall of the annular pocket, the secondelastomeric seal filling the second annular groove when the annular bodysaver is completely inserted into the annular pocket of the valve bodyand the annular body saver has a preloaded metal to metal contact withthe valve body, whereby there is no gap between the end wall of theannular pocket and the first end wall of the annular body saver.
 19. Thehigh pressure valve of claim 12, further comprising a third elastomericseal disposed in a third annular groove formed in the second end wall ofthe annular body saver, the third elastomeric seal filling the thirdannular groove when the seal insert is inserted into the second pocketof the valve body, whereby there is no gap between the third elastomericseal and the first end wall of the seal insert.
 20. The high pressurevalve of claim 12, wherein the movable member comprises a plug.